Balanced armature devices are used in audio applications such as miniature speakers for hearing aids. Moving coil loudspeakers are more commonly used for larger devices such as home entertainment systems, but moving coil speakers are too inefficient for use in miniature applications. However, conventional balanced armature devices typically suffer from undesirable distortion.
There would be great commercial benefits to the development of reduced distortion balanced armature devices, and further it would be very useful to design structures having a desired magnetic responses for various applications.